Sheet material dispensers are designed to dispense individual sheet material from various sources including folded sheet material and rolled sheet material. Each type of sheet material source requires a different means of dispensing the sheet material. As a result, each source has unique problems in controlling how much sheet material is dispensed, and how quickly more sheet material is made available.
Folded sheet material dispensers contain separate sheets of folded sheet material that are dispensed through an opening. When a user removes a single sheet from the opening, another individual sheet is instantly made available. As a result, several sheets can be removed at once. Because the sheets are so readily available, there is no real limit to how many sheets can be removed by the user. Therefore, folded sheet material dispensers must by constantly checked to make sure they are full.
One common type of sheet dispenser dispenses sheet material wound on rolls. These dispensers have several different means of dispensing paper. The sheets can be removed by either pulling on a free end of a sheet or actuating a lever to advance the sheet. These dispensers usually have a cutter to sever the individual sheet from the source of sheet material. The cutter can be arranged adjacent to the opening, in which case the user removing the sheet must force the sheet against the cutter. Otherwise, the cutter is formed as part of a cutting drum mechanism.
The most simple dispensers rely on the user to pull on a free end of sheet material, thereby causing the sheet material to be dispensed. The amount of force necessary to dispense the sheet material depends in part on the location of the cutter. It takes more force to remove an individual sheet where the cutter is part of a cutting drum mechanism as compared to when the cutter is located adjacent to the opening. When the cutter is part of the cutting drum mechanism, it is the rotational momentum of the cutting drum that severs the individual sheet from the sheet material roll. To obtain the required amount of rotational momentum, the user has to apply more force than simply pulling the sheet material against the cutter.
Due to relatively recent advances in paper making technology that permit relatively easy formation of perforations in sheet material, there are now a number of dispensers capable of dispensing sheet material having spaced rows of preformed perforations. Such perforations weaken the sheet material, making it easier to separate an individual sheet from the remainder of sheet material. Some conventional dispensers for this type of sheet material have drawbacks and disadvantages. For example, these dispensers are designed so that after an individual sheet is dispensed, a sufficient length (tail end) of sheet material normally remains extended from the dispensing outlet to be grasped by the next user. Sometimes, however, when the sheet material tears along a perforation line positioned inside the dispenser, there is little or no exposed length of sheet material that can be grasped. In some cases, this requires the next user to actuate a manual lever or crank that could spread germs or other contaminants from one user to another.
The present inventors have proposed to improve sheet material dispensing by providing a sheet material dispenser with perforation detecting capability, for example. Such detection, however, is challenging because the translucence of the some types of sheet material may provide false indications of perforations.
In light of the foregoing, there is a need in the art for an improved dispenser and method for dispensing sheet material.